Pulse oximetry is a procedure used to measure the oxygen level (or oxygen saturation) in the blood. It is considered to be a noninvasive, painless, general indicator of oxygen delivery to the peripheral tissues (such as the finger, earlobe, or nose).ulse oximetry is a procedure used to measure the oxygen level (or oxygen saturation) in the blood. It is considered to be a noninvasive, painless, general indicator of oxygen delivery to the peripheral tissues (such as the finger, earlobe, or nose).
The area of the World Ocean is about 361.9 million square kilometers (139.7 million square miles), which covers about 70.9% of Earth's surface, and its volume is approximately 1.335 billion cubic kilometers (320.3 million cubic miles).
This includes not just the surface of the Earth, but inside as well. Scientists calculate that the total mass of the oceans on Earth is 1.35 x 10 18 metric tonnes, which is 1/4400 the total mass of the Earth. In other words, while the oceans cover 71% of the Earth's surface, they only account for 0.02% of our planet's total mass.